Field of the Invention
The present invention relates to a configuration for promptly supplying liquid in a liquid ejecting head.
Description of the Related Art
In a liquid ejecting apparatus such as an inkjet printing apparatus, there is demand for a stable supply of liquid to an ejecting head that ejects the liquid as droplets. Particularly, in a color inkjet printing apparatus that uses multiple ink colors, a supply channel for guiding ink to ejecting elements is provided independently for each ink color, and prompt supply is demanded for each.
Meanwhile, in a serial inkjet printing apparatus, an on-carriage method and an off-carriage method may be adopted as the method of supplying ink to a print head. The on-carriage method refers to a format of mounting an ink tank that supplies ink to an ejecting head on a carriage that moves inside the apparatus together with the ejecting head. On the other hand, the off-carriage method refers to a method of affixing a main ink tank at a designated location in the apparatus, and supplying ink through a flexible tube to an ejecting head that moves together with the carriage. In the case of a comparatively large-scale printing apparatus, the on-carriage method has a risk of imposing too great a load on the carriage bearing a high-capacity ink tank, and thus the off-carriage method is often adopted.
Japanese Patent Laid-Open No. 2012-45805 discloses an ink supply configuration for the off-carriage method. FIGS. 6A and 6B are diagrams illustrating the configuration of a joint unit of a sub tank disclosed in Japanese Patent Laid-Open No. 2012-45805. Herein, the sub tank refers to a configuration which includes liquid chambers corresponding to the types of ink, and which is movable together with the carriage while supplying each ejecting head with ink from each liquid chamber.
A joint needle unit 300 is made up of a flat plate, and integrally supports multiple joint needles 302 formed approximately perpendicularly to the flat face. Additionally, by having positioning pins 301a and 301b arranged on the joint needle unit 300 engage with positioning openings 401a and 401b on the sub tank side, the multiple joint needles 302 are also inserted into joint openings 402 on the sub tank side. As a result, ink supplied from tubes is made to enter the liquid chambers. Japanese Patent Laid-Open No. 2012-45805 discloses a configuration that increases the positioning accuracy of the individual joint needles and decreases the risk of ink leakage by providing features to the layout of the positioning units 401a and 401b and the multiple joint needles 302.
However, although the configuration of Japanese Patent Laid-Open No. 2012-45805 achieves increased positional accuracy of the joint needles in the plane of the joint unit, or in other words a direction perpendicular to the direction of joint needle insertion, the configuration of Japanese Patent Laid-Open No. 2012-45805 does not consider the force produced in the direction of joint needle insertion and removal. For this reason, if the number of ink colors to handle is increased, and the force produced in the direction of joint needle insertion and removal becomes larger, there is a risk of damage to comparatively weak portions, such as the coupling face of the sub tank and the ejecting head, and a risk of seal rupture.